Recovery of nickel from nickel containing iron ores



Aug. 2o, 1940.

K M. SIMPSON RECOVERY OF NIOKEL FROM NICKEL CONTAINING IRON ORES FiledFeb. 7, 1953 Patented Aug. 20, 1940 nuovi-:RY or' NICKEL Faoin NICKELooN'rAnvmG moN omis Kenneth M. Simpson, New York, N. Y. ApplicationFebruary "l, 1939, Serial No. l255,146

'JClaima This invention relates to the recovery of nickel from nickelcontaining iron ores, and more particularly to a process in which nickelcarbonyl is formed, separated from the ore and decoml posed to producesubstantially pure nickel.

\ In accordance with the present invention, I have found that many ironorescontaining small amounts of nickel can be treated by a carbonylprocess to recover substantially pure nickel from 10 the iron orewithout preliminary treating of the ore to remove the iron. 'I'hat is tosay, the extremely expensive and time consuming steps of first forming amatte substantially i'ree from iron are eliminated as the nickel isremoved from 1I the ore as nickel carbonyl in the presence of iron.

Many iron ores occur in the oxide form substantially free of sulfur butcontain appreciable quantities of nickel for which no practical processhas heretofore been known for removing the nickel. In accordance withthe present invention, most of the nickel can be removed from the ironore as the primary product of the process and the iron ore itself isimproved so that it can be directly smelted into iron usable for manypuru poses.

In the preferred process, an ore containing iron and nickel, in whichthe metals, or at least the nickel, occur as oxides or have beenconverted to oxides, is ground, if necessary, in a ball mill u or otherapparatus. The ore is selectively reduced so as to reduce nickeloxideswithout reducing substantial quantities of iron oxides, and then treatedwith carbon monoxide to form nickel carbonyl, which is then decomposedto produce u substantially pure nickel. In a'modication of the process,a substantial amount of the iron may also be reduced and substantialamounts of iron carbonvls also formed by. suitable treatingtemperatures.-The present invention also contemplates steps forseparating the yiron c'ar nyl from the nickel carbonyl so that`substanti ly pure nickel carbonyl can be decomposed into'substantiallypure nickel. The separatediron carbonyl can also be decomposed torecover substanu tiallypure iron.

It is, therefore, an object of the presentinvention to provide a processof recovering nickel from iron ores containing the same, withoutnecessitating the removal of the iron prior-to treatment n of the orefor the recovery of nickel.

Another' object of the invention is to provide a process of selectivelyreducing nickel oxide from an iron oxide ore containing f'nickel oxideand separating the reduced nickel from the ore in the n form of acarbonyl.

A further object of the invention is to provide a process of recoveringnickel from a reduced ore containing iron in which iron and nickelcarbonyls are formed, the iron carbonyl separated from nickel carbonyland the nickel carbonyl 5 thereafter decomposed to produce substantiallypure nickel.

A still further object of the invention is to provide a process ofseparately recovering nickel i and iron from ores containing the sameby. con` 10 verting nickel. and iron in the ore to carbonyls, separatingthe nickel and iron -carbonyls and separately decomposing the same.

Other objects and advantages of the' invention will appear in thefollowing description of pre- 15 ferred embodiments of the inventionmade in accordance with the attached drawing, which shows a flow sheetof a preferred process;

As shown in the drawing, the iron oxide ore containing nickel oxideiswithdrawn -from a 20 source I and, if necessary, dried in a dryer 2 andconverted to finely divided form in a pulverizer 3. The ore is thenintroduced into a reducing retort 4 in which, in the preferredoperation, the nickel oxide is reduced to metallic nickel without reduc-25 ing substantial quantities of iron oxide to metallic iron. I havefound that this may be accomplished by maintaining a y temperature inthe reducer of between approximately v350 and 500 C. and preferablyabout 350 C. The reducing 30 gas ordinarily used is either water gas orproducer s gas, preferably producer gas obtained from a producer 5 anddelivered to the reducing retort l by a gas pump i. Since .the reducinggas is ordinarily produced at a relatively high temperature, 35

I preferably employ the heat thereof in maintaining the reducing retort4 at the desired temperature. All or a portion of the spent reducing gasmay be withdrawn from the reducing retort 4 through a conduit 'I anddelivered to a burner o l positioned in a housing 9 belowl the reducingretort. A cylindrical retort rotated about a horizontal axis ispreferred, but any suitable apparatus capable of repeatedly bringing theore particles into contact with the reducing gas may 5 be employed. Itwill be understoodl that the reducing retort is closed against theescape of gas and that suitable mechanism may be employed forintroducing and withdrawing ore. The reducing retort is preferablymaintained under `a. 5o low superatmospheric pressure, for example, 2pounds per square inch. At the temperatures mentioned, substantially allof the nickel oxidecan be reduced without reducing substantialquantities of ironl oxides, particularly if the ore is is withdrawn fromthe reducer as soon as nickel oxide reduction has progressed to thedesired v extent.

'I'he ore withdrawn from the reducer is -de livered to an ore cooler Iin which the temperature of the ore is lowered to between 40 and 80 capeof the gas and is preferably operated under a low superatmosphericpressure, for example, 2 pounds per square inch. Suitable closedconveying means (not shown) are employed to-transfer the ore from thereducing retort 4 to the ore cooler I0 and from the ore cooler I0 to thegasifier I in order to prevent contact between the ore and the externalatmosphere. A temperature of between 40 and 80 C. is maintained in thegasierf The carbon monoxide combines with the nickel at thesetemperatures to produce nickel carbonyl and a gas rich in nickelcarbonyl is withdrawn from the vaporizer through a conduit I3 anddelivered to a decomposer I4. -.The iron ore from which nickel hasbeenseparated is discharged from-the process as indicated at I5.. It will beunderstood that the process may be operated to reduce only a portion ofthe nickel in the reducing retort 4, in which case a portion of the oreremoved from the gasifler Il may be recycled through the reducing retort4 or through another reducing retort and then back to the gasier II.Alternatively, the ore discharged from the gasifier II may be subjectedto further reducing and gasifying steps inu other reducing retorts andgasiflers in order to remove additional nickel therefrom. In any case,the gas rich in nickel carbonyl 'is delivered to a decomposer I4.

In the decomposer I4 the gas rich in nickel carbonyl is heated to adecomposing temperature, for example a temperature above 200 C. Thenickel carbonyl decomposes to liberate metallic nickel, which isdeposited in the decomposer, and carbon monoxide. The nickel may bedeposited as solid masses in a great variety of shapes, such ascylinders or long tubes. composer comprises a series of tubes I5 whichmay be positioned in a heating chamber I6 through which any desiredheating medium such as products of combustion may be circulated.

The carbon monoxide rich gas formed in the decomposer is withdrawnthrough a conduit and delivered to a gas storage tank I8 from which itis recirculated by a pump Iilfthrough the gasifler II to form additionalnickel carbonyl which is vdecomposed in the decomposerl I4 to againliberate carbon monoxide rich gas.

In some cases it is desirable to cause a substantial amount of ironoxide to be reduced in the reducing retort 4 with 'consequent productionof iron carbonyl in the gasifier I I. The highuble in such solvents asbenzene or alcohol.

@carbonyl before the latter is delivered to the decomposer. This may beaccomplished in several ways in accordance with the present invention.Both iron carbonyl Aand nickel carbonyl are solthe nickel carbonyl andiron carbonyl have considerably different boilirg points, the boilingPreferably the depoint of nickel carbonyl being about 43 C. and theboiling point of iron pentacarbonyl .being about 103 C., the nickel andiron carbonyls may be dissolved in such a solventand then selectivelyvolatiiized from the solvent, for example, in a still and fractionatingcolumn. Furthermore, both the nickel and iron carbonyls can be reducedto liquid form by cooling the same below their boiling points. Sinceiron carbonyl has considerably higher boiling point than the nickelcarbonyl, it can be selectively condensed from the mixture of gases. Onthe other hand, lboth the iron and nickel carbonyl can be cooled toliquid form and the nickel carbonyl separated from the iron carbonyl byfractional distillation. In any event, the nickel carbonyl can be freedof iron carbonyl to any desired extent by employing one or more of thesteps above discussed, such that substantially pure nickel is producedwhen the nickel carbonyl is decomposed. The iron carbonyl separated fromthe nickel carbonyl is also preferably decomposed in a decomposer (notshown) so that the iron is recovered and the carbon monoxide resultingfrom the decomposition made available for use in the gasiiler.l

The process above described is particularly aplar ores. The Cuban oresreferred to occur in -the eastern portion oi' that island; Thesedeposits are of great extent and large tonnages of iron ore existcarrying from .05 to 1.75% nickel and from .05 to .2% cobalt. The nickelinV these ores occurs as an oxide or a hydroxide, the term' oxide beingemployed elsewhere in the specification and in the claims as beinginclusive of both forms. The nickel is in a microscopic state ofdivision such that very little grinding of the ore is required beforeremoving the nickel.

While I have described the preferred embodiments of my invention, it isunderstood that the details may be varied within the scope of thefollowing claims.

What I claim is: l

l. The processof recovering substantially pure nickel from iron oxideores containing relatively small amountsof nickel oxide, whichcomprises, selectively reducing said ore to reduce the major portion ofsaid nickel oxide while retarding the reduction of iron oxide, treatingthe reduced ore with carbon monoxide at a temperature between 40 and 80C. to form :gaseous nickel carbonyl containing a relatively small amountof gaseous iron carbonyl, separating the iron carbonyl vfrom the nickelcarbonyl and decomposing said nickel carbonyl to produce substantiallypure nickel.

2. The process of recovering nickel from iron ores containing relativelysmall amounts of nickel oxide, which comprises, reducing said ores toconvert nickel to metallic form while retarding the conversion of ironto metallic form, treating the reduced ore with carbon monoxide to formnickel carbonyl vapor admixed with a relatively small amount of ironcarbonyl vapor, separating the iron carbonyl vapor from said nickelcarbonyl vapor and decomposing the nickel carbonyl to deposit metallicnickel.

3. The process of recovering nickel from iron ores containing relativelysmall amounts of nickeloxide, which comprises, reducing said ores toconvert nickel to metallic form while retarding the conversion of saidiron to metallic form, treating the reduced ore with carbon monoxide toplicable to certain ores found .in large quantities f in Cuba, althoughit is applicable to other simiform nickel carbonyl vapor admixed with asmall amount oi'I iron carbonyl vapor, separating the fil ` nickelcarbonyl vapor from the iron carbonyl nickel carbonyl from the ironcarbonyl by utilizing the difference in the boiling points 'of thenickel carbonyl and iron carbonylv and heating nickel carbonyl vapor todecompose the same and deposit metallic nickel.

4. The process of recovering substantially pure nickel from iron oxideores containing relatively small amounts oi' nickel oxide, whichcomprises, selectively reducing said ore. without a prior smelting stepto reduce nickel nickel oxide While retarding the reduction of ironoxide, treating the reduced ore with carbon monoxide at a temperaturebetween 40 and 80 C. to form gaseous nickel carbonyl containing a.relatively small amount of gaseous iron carbonyl, separating the ironcarbonyl from the nickel carbonyl and de composing said nickel carbonylto produce substantially pure nickel.

5. The process of recovering nickel from iron ores containing relativelysmall amounts of nickel oxide, which comprises, reducing said ores toconvert nickel to metallic form while retarding the conversion oi ironto metallic form, treating the reduced ore with carbon monoxide to formnickel carbonyl vapor admixed with a relatively small amount of ironcarbonyl vapor, separating the vapor by dissolving said carbonyls in asolvent therefor, fractionally distilling the nickel carbonyl from theresulting solution and decomposing the same to deposit metallic nickel.

6. The process of recovering nickel from iron ores containing relativelysmall amounts of nickel oxide, which comprises, reducing said ores toconvert nickel to metallic form while retarding the conversion of ironto metallic form, treating the reduced ore with carbon monoxide to formnickel carbonyl vapor admixed with a relatively small amount of ironcarbonyl vapor, separating'the nickel carbonyl vapor from the ironcarbonyl va.- por by fractionally condensing said vapors, anddecomposing the nickel carbonyl to deposit metallic nickel.

7. The process of recovering nickel from iron ores containing relativelysmall amounts of nickel oxide, which comprises, reducing said ores toconvert nickel to metallic form while retarding the conversion of ironto metallic form, separating the nickel carbonyl vapor from the ironcarbonyl vapor by condensing said vapors, fractionally distilling nickelcarbonyl from said iron carbonyl, and decomposing the nickel carbonyl todeposi metallic nickel.l

IGlNNETH M. SIMPSON.

